A National Security Agency police officer opened fire Wednesday morning on a vehicle at an entrance to the intelligence agency's campus in Maryland, law enforcement sources told CBS News. Three people were injured when the SUV slammed into a security barrier.

The three people in the vehicle, who the FBI only identified as men, were in custody and being questioned by authorities. One person in custody appeared to be cooperating, CBS News justice and homeland security correspondent Jeff Pegues reports.

In a statement, the NSA said an unauthorized vehicle attempted to enter the agency's campus in Fort Meade, Maryland, northeast of Washington, shortly after 7 a.m. and "weapons were discharged in the course of the incident." The situation was under control, and there was no ongoing threat, the NSA said.

At an afternoon press conference, FBI Special Agent Gordon Johnson wouldn't comment on the three individuals in custody other than to say they were men and that the driver was among the injured.

Johnson identified the other injured people as the NSA officer and a civilian. He didn't provide other details.

There didn't appear to be a nexus to terrorism, Johnson said.

Fort Meade incident update: we do not believe there is any nexus to terrorism at this point in time, and believe that this was an isolated incident. We ask for your patience as the investigation continues.

In the early hours of the shooting, law enforcement sources confirmed that they were investigating whether a Maryland State Police vehicle was tailing the suspects shortly before the shooting. But later in the day investigators determined that that was not the case and Maryland State Police denied that they had any involvement in the incident.

The vehicle was described as a black Dodge Durango with New York license plates that had been rented at Enterprise, Pegues and CBS News senior investigative producer Pat Milton report.

Investigators were looking into whether the vehicle ended up on NSA property by accident and the driver tried to drive away and didn't stop when told to, which resulted in the officer opening fire, Pegues reports.

Aerial footage showed the SUV stopped at the gate. Bullet holes were seen in the vehicle's windshield, but two officials told CBS News that no one was hit by gunfire. Johnson said the driver was rushed to a hospital with injuries sustained from the crash.

Johnson wouldn't say whether any weapons were found in the vehicle.

NSA police, the FBI and local law enforcement responded to the shooting, sources told CBS News.

White House deputy press secretary Lindsay Walters said in a statement that President Trump had been briefed on the shooting.

"Our thoughts and prayers are with everyone that has been affected," Walters said.

After the shooting, authorities closed a major highway in both directions, causing major backups throughout the area during rush hour.

Despite prominent highway signs, drivers occasionally take the wrong exit and end up at the tightly secured gates. Most motorists then carefully follow the orders of heavily armed federal officers and turn around without getting into more trouble.

But in early 2015, two people were shot at by NSA police when they disobeyed orders outside the heavily secured campus. One driver died at the scene after NSA police opened fire on a stolen sports utility vehicle. Authorities later said they had stolen a car from a man who picked them up for a party at a motel.

Editor's note: An earlier version of this report said that the vehicle was being tailed by the Maryland State Police, but the FBI and Maryland State Police later said that this was not the case.